1. Field of the Disclosure
The present disclosure is directed to a radio frequency identification (RFID) tag adapted for use in extreme environmental conditions, the encasement of the tag within a metal shell for protection, and the use of the metal shell for radio frequency (RF) coupling.
2. Technical Background
Radio frequency identification (RFID) chips are attached to products for a variety of business reasons, including asset tracking, inventory, and other informational purposes. These uses are sometimes called “RFID tagging”. RFID tagging has become increasingly common. Since the advent of second generation Ultra-High Frequency (UHF) standards (i.e. ISO-18000-6c), RFID tagging applications have grown at a rate greater than twenty percent (20%) per year according to some estimates. RFID tag volumes have increased to tens of millions per year and are trending upwards.
Many RFID applications entail specific performance requirements depending on environment and other specifications, one of which may be communication range. RFID communication range is often an important requirement that affects antenna design. Currently, many RFID applications use a standard dipole antenna. The dipole antenna RFID tag may use a metal foil antenna that is directly bonded or capacitively coupled to the RFID chip.
Standard RFID tags tend to be fragile and susceptible to cracking at the RFID chip to antenna interface, or within the antenna itself, and are unstable when exposed to elevated temperatures. This instability does not alleviate the need for RFID tags that operate in extreme environmental conditions.